exampleapplet.java

java语言规范

/*
 * Copyright 2002 Sun Microsystems, Inc. All  Rights Reserved.
 *  
 * Redistribution and use in source and binary forms, with or 
 * without modification, are permitted provided that the following 
 * conditions are met:
 * 
 * -Redistributions of source code must retain the above copyright  
 *  notice, this list of conditions and the following disclaimer.
 * 
 * -Redistribution in binary form must reproduce the above copyright 
 *  notice, this list of conditions and the following disclaimer in 
 *  the documentation and/or other materials provided with the 
 *  distribution.
 *  
 * Neither the name of Sun Microsystems, Inc. or the names of 
 * contributors may be used to endorse or promote products derived 
 * from this software without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any 
 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND 
 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY 
 * EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY 
 * DAMAGES OR LIABILITIES  SUFFERED BY LICENSEE AS A RESULT OF OR 
 * RELATING TO USE, MODIFICATION OR DISTRIBUTION OF THE SOFTWARE OR 
 * ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE 
 * FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, 
 * SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER 
 * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF 
 * THE USE OF OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN 
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 *  
 * You acknowledge that Software is not designed, licensed or 
 * intended for use in the design, construction, operation or 
 * maintenance of any nuclear facility. 
 */

package actual;

import java.applet.*;
import java.lang.*;
import java.util.*;
import java.awt.*;

/**
 * ExampleApplet: Applet that demonstrates the
 * Spinner component.
 *
 * The applet creates a window that has a pretty 
 * background picture in it, and throws some lightweight
 * Spinner components in. Notice how the lightweight
 * Spinner component has "transparent" areas that let you see
 * the image behind it! Cool!
 */
public class ExampleApplet extends Applet {

  Image orb;

  GridBagLayout gridbag = new GridBagLayout();
  GridBagConstraints c = new GridBagConstraints();

  public void init() {
      setLayout(gridbag);

      loadBackgroundImage();
      initializeGridbag();

      // ************* Create Spinners
      Spinner  spinner1  = new Spinner();
      Spinner  spinner2  = new Spinner();

      // Set the color of the two spinners
      spinner1.setBackground(Color.yellow);
      spinner1.setForeground(Color.red);

      spinner2.setBackground(new Color(100, 0, 255));
      spinner2.setForeground(new Color(50, 255, 255));

      // ************* add components
      // add spinner1 
      c.gridx = 0;     c.gridy = 0;
      gridbag.setConstraints(spinner1, c);
      add(spinner1);

      // add spinner2
      c.gridx = 1;     c.gridy = 1;
      gridbag.setConstraints(spinner2, c);
      add(spinner2);

      spinner1.startSpinning();
      spinner2.startSpinning();
  }

  public void initializeGridbag() {
      c.gridwidth = 1; c.gridheight = 1;
      c.weightx = 1;   c.weighty = 1;
      c.fill = GridBagConstraints.BOTH;
      c.anchor= GridBagConstraints.NORTHWEST;
  }

  public void loadBackgroundImage() {
    //needed because ExampleApplet is running under Switcher
    Applet parentApplet;
    
    //Get the parent Applet object. 
    try {
      parentApplet = (Applet)getParent();
      orb = parentApplet.getImage(parentApplet.getCodeBase(), 
				  "actual/images/orb.gif"); 
    } catch (ClassCastException e) {
      System.err.println("Parent isn't an Applet!");
      throw(e);
    }
  }
  
  /**
   * override update to *not* erase the background before painting
   */
  public void update(Graphics g) {
      paint(g);
  }
 
  /**
   * paint the background picture, then call super.paint which
   * will paint all contained components 
   */
  public void paint(Graphics g) {
      g.drawImage(orb, 0, 0, getSize().width, getSize().height, 
		  getBackground(), this);
      super.paint(g);
  }

}